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38results about How to "Reduce current amplitude" patented technology
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Multi-parameter monitoring system
InactiveUS7007541B2Minimizes current driveReduce current amplitudeTesting waterMeasurement apparatus housingsEngineeringWater quality
A plurality of multi-parameter monitoring tool assemblies are connectable over a communications network and are further in communication with a central controller. Each of the tool assemblies is configured to interconnect with one or more sensor head components which may be employable in the monitoring of water quality. According to the system described herein, the central controller may periodically communicate with one or more of the tool assemblies connected in the communications network and extract, process, and display information as to the configuration and operation of one or more tool assemblies.
Owner:INSITU INC
Method for providing enhanced stability of a vehicle with a deflated tire
ActiveUS7677095B1Improve stabilityReduce current amplitudeBrake control systemsVehicle steering/rolling behaviourControl theoryMotorized vehicle
In a motor vehicle equipped with pneumatic tires and a hydraulically actuated wheel brake system, a method for enhancing stability of the vehicle by determining whether any tire on the vehicle is deflated, determining the current magnitude of brake pressure at the wheel of the deflated tire when the brakes are applied, and reducing the current magnitude of brake pressure at the wheel of the deflated tire.
Owner:KELSEY HAYES CO
Dual-stator structure type high temperature superconducting permanent magnet wind driven generator
InactiveCN103780036ANo rotary seal issuesImprove reliabilityMagnetic circuit rotating partsCooling/ventillation arrangementLow speedHigh temperature superconducting
The invention discloses a dual-stator structure type high temperature superconducting permanent magnet wind driven generator. In the housing, the rotor is a hollow cup-shaped rotor, the bottom portion of the rotor is fixedly connected with a spindle, permanent magnets are attached and distributed uniformly and separately on inner and outer walls of the rotor in the circumferential direction; inner and outer stators are arranged inside and outside the rotor in the circumferential direction separately, an air gap exists between the inner and the outer stators and the permanent magnets on the inner and outer walls of the rotor; outer stator grooves are distributed uniformly and separately on the inner side of the outer stator in the circumferential direction, a first superconducting armature winding is wound on two adjacent outer stator grooves; inner stator grooves are distributed uniformly and separately on the outer side of the inner stator in the circumferential direction, a second superconducting armature winding is wound on two adjacent inner stator grooves, and the first and second superconducting armature windings are sealed through first and second cooling devices separately. The wind driven generator of the invention adopts the dual-stator structure, so the rotary sealing problem with cooling liquid does not exist, advantages of simple and reliable structure, less loss and high power density can be realized, and the wind driven generator is suitable for direct drive type low-speed wind turbine generator systems.
Owner:ZHEJIANG UNIV
Direct current capacitor harmonic current suppression method
ActiveCN107017762AReduced harmonic content and current amplitudeReduce harmonic contentAc-ac conversionPower inverterRectiformer
Disclosed is a direct current capacitor harmonic current suppression method. Back-to-back converters are adopted; the active direct current link capacitor current in the back-to-back converters is from superposition of direct currents of a rectifier i<dcr> and an inverter i<dci>; the phases of harmonic components in the two currents i<dcr> and i<dci>are determined by the relative phase PWM carrier waves of the rectifier and the inverter; and by actively controlling and regulating the frequencies and phases of PWM carrier waves in the rectifier and the inverter, the direct current link harmonic currents from the two converter levels can be the same in phases, so that the capacitor harmonic current minimization can be achieved. By adoption of the direct current capacitor harmonic current suppression method provided by the invention, harmonic contents and current amplitudes in the first and second carrier frequency bands in the direct current link capacitor current can be obviously lowered; and by virtue of the method, the power supply mass specification can be satisfied and capacitor current harmonic can be effectively reduced without using a high-capacity direct current link capacitor.
Owner:CHINA THREE GORGES UNIV
30-slot 14-pole fractional-slot double-layer short-distance distribution winding 15-phase permanent magnet synchronous motor
ActiveCN105846628AReduce current amplitudeIncrease profitMagnetic circuit rotating partsMagnetic circuit stationary partsLow speedShortest distance
The invention discloses a 30-slot 14-pole fractional-slot double-layer short-distance distribution winding 15-phase permanent magnet synchronous motor. Fifteen phase windings are divided into three groups. The axes of five phase windings in one group are separated from one another for 72 DEG, and the five phase windings are connected for forming a five-phase star-connected symmetrical winding. The axes of the five-phase star-connected symmetrical windings which correspond with one another in the three groups are successively shifted by 12 DEG. Three natural points in the three groups of five-phase star-connected symmetrical windings are not connected with one other. The number of slots on each phase of each pole is a fractional number. The span of each coil is 2 slots. The end of the coil is relatively short, thereby saving copper and realizing small copper consumption amount. When a fundamental wave current is input into each star-connected symmetrical winding, a third harmonic current of which the amplitude is one sixth of the amplitude of the fundamental wave current can be simultaneously input. After the third harmonic current is input, not only is current amplitude of a power switch tube reduced, but also ferromagnetic saturation of the motor is reduced, and furthermore ferromagnetic material utilization rate and torque density are improved. A large-power low-speed permanent-magnet synchronous motor which is composed of a plurality of unit motors has advantages of high efficiency and relatively low vibration noise.
Owner:安徽登冠新能源电动车科技有限公司
Zero-voltage switching pulse-width modulation converter
ActiveCN103780087AReduce current amplitudeReduce lossDc-dc conversionElectric variable regulationPower flowTransformer
The invention belongs to the field of electric energy transformers, and provides a zero-voltage switching pulse-width modulation converter. A reset circuit is added in the converter on the basis of an existing main circuit and an existing auxiliary circuit, and the reset circuit comprises a reset switching tube and a reset diode. Under the working condition that only an auxiliary switching tube is turned on after the reset switching tube is turned off, a current in an auxiliary inductor flows in output voltages or an input power supply of the converter through the reset diode and related elements in the auxiliary circuit, thus the amplitude of the current in the auxiliary inductor drops to zero rapidly, zero-current turning-on of the auxiliary switching tube, the reset switching tube and the auxiliary inductor and zero-current turning-off of an auxiliary diode and a reset diode are achieved, therefore, it is guaranteed that elements in the auxiliary circuit and elements in the rest circuit are low in loss, and safe and reliable operation of the converter in a whole on-off operating period under the working conditions of a full input voltage range, a full load range and the like is guaranteed.
Owner:SHENZHEN CLOU ELECTRONICS +2
Reactive compensation and vector control method for doubly-fed wind turbine generator
ActiveCN110571873AImprove the ability of low voltage ride throughImprove running characteristicsFlexible AC transmissionSingle network parallel feeding arrangementsOvervoltageNew energy
The invention relates to a reactive compensation and vector control method for a doubly-fed wind turbine generator, and belongs to the technical field of operation and control of doubly-fed wind turbine generators in new energy power generation. In order to avoid off-grid operation of the doubly-fed wind turbine generator caused by voltage drop of a power grid, the output reactive power of a gridside is adjusted in a reactive power compensation mode by changing a grid side converter control method on the one hand; and on the other hand, in consideration of transient characteristics of a stator flux linkage during a voltage drop period, a rotor side converter adds a stator flux linkage change item caused by the voltage drop on the basis of the traditional vector control method, and the DCside overvoltage and the rotor side overcurrent are suppressed during the voltage drop period and after the fault is removed so as to help the recovery of the system voltage. For research of a grid-side and rotor-side converter cooperative control method, off-grid operation of the doubly-fed wind turbine generator caused by the voltage drop of the power grid can be effectively avoided, the systemfault voltage is helped to be recovered, and the stability of the power grid is maintained.
Owner:YANSHAN UNIV
Arc extinguishing and lightning protection method based on liquid-electric effect and Pascal principle
PendingCN113725733AReduce the steepnessReduce current amplitudeSpark gap detailsInsulatorsMechanical engineeringArc extinction
The invention discloses an arc extinguishing and lightning protection method based on a liquid-electric effect and a Pascal principle, and belongs to the technical field of arc extinguishing and lightning protection. The method comprises the steps that a sealing pipe is arranged, an upper electrode and a lower electrode are arranged at the two ends of the sealing pipe in a sealed mode respectively, insulating oil is arranged in the sealing pipe, a skirt edge is arranged on the side edge of the sealing pipe, when arc discharge is caused in the sealing pipe filled with the insulating oil, the electro-hydraulic effect generates impact waves rushing to the side wall, the Pascal effect enhances the electro-hydraulic effect, when the arc acts on the insulating oil and the pressure intensity of a certain part of the static insulating oil is changed, the arc is transmitted to all directions of the inner side of the sealing pipe without changing, impact waves of the liquid-electric effect and the Pascal effect impact the side edge and then return to impact, the arc channel which is aligned with the center is concentrated for impact arc extinguishing, and arc extinguishing is completed. According to the invention, the electric arc is cut off rapidly, the electric arc discharges in the liquid to generate a liquid-electric effect, impact pressure waves are formed rapidly, and the impact electric arc is cut off immediately when being formed.
Owner:南宁超伏电气科技有限公司
Deadbeat direct torque control method for switched reluctance motor
ActiveCN109546918AHigh precisionReduce torque rippleElectronic commutation motor controlAC motor controlVoltage vectorPosition angle
The invention provides a deadbeat direct torque control method for a switched reluctance motor. The deadbeat direct torque control method comprises the following steps: calculating a position angle ofa rotor by a photoelectric encoder and calculating a magnetic flux and current of a motor in a rotating coordinate system; giving a flux linkage and three-phase voltages and currents under the statorcoordinate system according to a difference between a given torque and a feedback torque; calculating a space voltage vector for controlling running of the motor in the rotating coordinate system ina next beat; and acquiring six-path pulse signals to control the motor. According to the invention, the torque and the flux linkage are controlled directly by controlling two-phase reference voltagesin the rotating reference coordinate system; and the torque and the flux linkage are controlled within one control cycle, so that the torque pulsation and the flux linkage are reduced substantially.
Owner:DALIAN MARITIME UNIVERSITY
Transient electromagnetic field excitation system for transcranial magnetic stimulation (TMS) in medical field
ActiveCN102614592BIncreased rate of change of excitation currentImprove securityElectrotherapyMagnetotherapyElectromagnetic fieldCharged current
Owner:刘冀成
Knitting member selecting actuator of knitting machine
A knitting member selecting actuator (1) of a knitting machine, wherein magnetic characteristic parts (35a, 35b, 45a, 45b, 55a, 55b) having magnetic resistances between the yokes (32a, 32b, 42a, 42b, 52a, 52b) of non-controllable sucking parts (7, 8, 9) positioned face to face increased larger than magnetic resistances between the yokes and the knitting members sucked on a sucking surface and decreased smaller than magnetic resistances between the yokes and the sucking surfaces of the controllable sucking parts (5, 6) adjacent to each other are provided between the yokes.
Owner:SHIMA SEIKI MFG LTD
Memory cell having a buried phase change region and method for fabricating the same
ActiveCN101872838AReduce current flowReduce current amplitudeSolid-state devicesDigital storageDielectricEngineering
Owner:MACRONIX INT CO LTD +1
Arc-extinguishing lightning protection device based on liquid-electric effect
PendingCN113594878AReduce the steepnessReduce current amplitudeSpark gap detailsCorona dischargeEngineeringMechanical engineering
The invention discloses an arc-extinguishing lightning protection device based on a liquid-electric effect, and belongs to the technical field of arc-extinguishing lightning protection, the arc-extinguishing lightning protection device is set to a sealing pipe, two ends of the sealing pipe are respectively provided with an upper electrode and a lower electrode which are arranged in a sealing manner, the sealing pipe is internally provided with insulating oil, and the side edge of the sealing pipe is provided with a skirt edge. The electric arc is cut off rapidly, the electric arc discharges in the liquid to generate a liquid-electric effect, impact pressure waves are formed rapidly, and the impact electric arc is cut off immediately when being formed. The reignition of the impact arc is delayed, the continuous discharge condition and the reignition condition are destroyed by high voltage in the ceramic tube, after the impact arc is cut off, the reignition breakdown time is greatly delayed by more than ten to dozens of microseconds, the gradient of lightning current is remarkably reduced by 90%, and the current amplitude is attenuated by more than 50%.
Owner:南宁超伏电气科技有限公司
Power system and control method thereof
ActiveUS20140218002A1Total current dropConstant output powerApparatus without intermediate ac conversionElectric variable regulationVoltage amplitudeElectric power system
The present invention provides a power system and controlling method thereof. The power system includes: pulse width modulation (PWM) power source, voltage detection unit, current detection unit and feedback signal generation unit. PWM power source receives external DC input, performs PWM on received external DC input, and supplies PWM output obtained through PWM from the DC output terminal to a device expecting power supply. Voltage detection unit detects voltage amplitude of PWM output. Current detection unit detects current amplitude of PWM output. Feedback signal generation unit generates feedback signal and supplies generated feedback signal to PWM power source. PWM power source adjusts the voltage amplitude and current amplitude of the PWM output based on the received feedback signal.
Owner:CHANGSHA HKC OPTOELECTRONICS CO LTD
Liquid recoil arc extinguishing lightning protection device
PendingCN113206451AReduce current amplitudeEnhanced arc extinguishing pressure characteristicsSpark gap detailsInsulatorsShock waveElectrical conductor
The invention discloses a liquid recoil arc extinguishing lightning protection device, and belongs to the technical field of arc extinguishing lightning protection. The device comprises a recoil pipe, a conductor is arranged at the bottom of the recoil pipe and connected to the ground, and liquid is arranged in the recoil pipe. Liquid is placed in the back-flushing pipe, when an electric arc enters the back-flushing pipe, the lightning arc impact time is extremely short at the moment that the electric arc pre-breaks through the liquid, the liquid cannot be deformed and displaced instantly, and the liquid-electric detonation effect and the back-flushing arc extinguishing pressure peak value are synchronous with the impact gradient electric arc pre-breakdown time; after the liquid is conducted by the electric arc, the electric arc and the liquid are subjected to heat exchange to generate an electro-hydraulic heat exchange effect, kinetic energy is stored through liquid bubbles generated by electric arc heat and a thermal evaporation effect, and downward shock waves generated by a hydraulic-electric detonation effect and the electro-hydraulic heat exchange effect are reflected back by the bottom of the recoil pipe to form a shock wave regular reflection effect for arc extinguishing. The arc is cut off early, the recoil arc extinguishing pressure peak value is synchronous with the impact large-gradient arc pre-breakdown time, and the impact arc is cut off immediately when the impact arc is just formed.
Owner:广西雷闪电气科技有限公司
Self-supplementing liquid recoil arc extinguishing device
PendingCN113206455AReduce the steepnessCause harmSpark gap detailsInsulatorsLiquid stateStructural engineering
The invention discloses a self-supplementing liquid-state back-flushing arc extinguishing device, and belongs to the technical field of lightning protection arc extinguishing. The self-supplementing liquid-state back-flushing arc extinguishing device comprises a back-flushing pipe, an automatic liquid supplementing bin and a liquid storage box; the back-flushing pipe is vertically and downwards arranged in an inverted mode, the bottom of the automatic liquid supplementing bin and the back-flushing pipe are arranged in a sealed mode, and the liquid storage box is arranged at the upper end of the automatic liquid supplementing bin and arranged in a sealed mode; a small plastic ball and liquid are placed in the liquid storage box, the small plastic ball sinks to the bottom of the liquid, the small plastic ball is arranged at the bottom in the back-flushing pipe to block the nozzle, and the liquid is stored in the back-flushing pipe. The arc extinguishing pressure of the cut-off arc reaches 100 barometric pressures, the recoil pressure is helped to act on the impact arc and cut off the impact arc, an arc building channel is cut off, the reignition of the impact arc is delayed, and the lasting and huge recoil pressure destroys the continuous discharge condition and the reignition condition.
Owner:广西雷闪电气科技有限公司
30-slot 14-pole fractional slot double-layer short-pitch distribution winding fifteen-phase permanent magnet synchronous motor
ActiveCN105846628BReduce current amplitudeIncrease profitMagnetic circuit rotating partsMagnetic circuit stationary partsLow speedShortest distance
The invention discloses a 30-slot 14-pole fractional-slot double-layer short-distance distribution winding 15-phase permanent magnet synchronous motor. Fifteen phase windings are divided into three groups. The axes of five phase windings in one group are separated from one another for 72 DEG, and the five phase windings are connected for forming a five-phase star-connected symmetrical winding. The axes of the five-phase star-connected symmetrical windings which correspond with one another in the three groups are successively shifted by 12 DEG. Three natural points in the three groups of five-phase star-connected symmetrical windings are not connected with one other. The number of slots on each phase of each pole is a fractional number. The span of each coil is 2 slots. The end of the coil is relatively short, thereby saving copper and realizing small copper consumption amount. When a fundamental wave current is input into each star-connected symmetrical winding, a third harmonic current of which the amplitude is one sixth of the amplitude of the fundamental wave current can be simultaneously input. After the third harmonic current is input, not only is current amplitude of a power switch tube reduced, but also ferromagnetic saturation of the motor is reduced, and furthermore ferromagnetic material utilization rate and torque density are improved. A large-power low-speed permanent-magnet synchronous motor which is composed of a plurality of unit motors has advantages of high efficiency and relatively low vibration noise.
Owner:安徽登冠新能源电动车科技有限公司
Liquid recoil arc extinguishing and lightning protection method
InactiveCN113328340AReduce current amplitudeEnhanced arc extinguishing pressure characteristicsSpark gap detailsInsulatorsShock waveEngineering
The invention discloses a liquid recoil arc extinguishing and lightning protection method, and belongs to the technical field of arc extinguishing and lightning protection. The method comprises the following steps: placing a liquid in a recoil pipe, when an electric arc enters the recoil pipe, at the moment when the electric arc pre-breaks down the liquid, generating a liquid-electric detonation effect due to that the lightning arc impact time is extremely short and the liquid cannot instantly deform and displace, enabling the peak value of the recoil arc extinguishing pressure to be synchronous with the pre-breakdown time of an impact steepness arc, immediately cutting off the impact arc when being formed, after the arc conducts liquid, enabling the arc and the liquid to exchange heat to generate an electro-hydraulic heat exchange effect, enabling liquid bubbles generated by arc heat and a heat evaporation effect to store kinetic energy, releasing the arc extinguishing pressure, and reflecting back downward shock waves generated by the electro-hydraulic detonation effect and the electro-hydraulic heat exchange effect back by the bottom of the recoil pipe to form shock wave regular reflection effect arc extinguishing. The arc is cut off early, the recoil arc extinguishing pressure peak value is synchronous with the impact large-gradient arc pre-breakdown time, the impact arc is cut off immediately when the impact arc is just formed, and the pressure of the cut-off arc is huge.
Owner:广西雷闪电气科技有限公司
Lightning protection device for multi-point arc shielding through liquid-electric effect pressure
InactiveCN113594861AReduce the steepnessReduce current amplitudeSpark gap detailsCorona dischargeMechanical engineeringArc extinction
The invention discloses a lightning protection device for multi-point arc shielding through liquid-electric effect pressure, and belongs to the technical field of arc extinguishing and lightning protection. The lightning protection device is set to be a sealing pipe, an upper electrode and a lower electrode are arranged at the two ends of the sealing pipe in a sealed mode respectively, insulating oil is arranged in the sealing pipe, and a skirt edge is arranged on the side edge of the sealing pipe; arc chutes are arranged on the inner side edge of the sealing pipe at intervals, and the transverse length of each arc chute is larger than one half of the inner diameter of the sealing pipe. The electric arc is cut off rapidly, the electric arc discharges in the liquid to generate a liquid-electric effect, impact pressure waves are formed rapidly, and the impact electric arc is cut off immediately when being formed. The reignition of the impact arc is delayed, the continuous discharge condition and the reignition condition are destroyed by high voltage in the ceramic tube, after the impact arc is cut off, the reignition breakdown time is greatly delayed by more than ten to dozens of microseconds, the gradient of lightning current is remarkably reduced by 90%, and the current amplitude is attenuated by more than 50%.
Owner:南宁超伏电气科技有限公司
Sealed arc extinguishing device capable of bearing high-strength pressure
The invention discloses a sealed arc extinguishing device capable of bearing high-strength pressure, which belongs to the technical field of lightning protection and arc extinguishing, and comprises a plastic sleeve, a steel sleeve, a ceramic tube, arc extinguishing insulating liquid, a conductive electrode and sealing silica gel, the conductive electrode is nested in the sealing silica gel, and the sealing silica gel is arranged at two ends of the ceramic tube in a sealing manner; the steel sleeve is fastened on the outer side of the joint of the sealing silica gel and the ceramic tube, the arc extinguishing insulating liquid is arranged in the ceramic tube, and the plastic sleeve is sleeved on the outer side of the steel sleeve and the ceramic tube. The electric arc discharges in the liquid to generate a liquid-electric effect, impact pressure waves are formed, the impact electric arc is immediately cut off when the impact electric arc is just formed, the continuous discharge condition and the reignition condition are damaged by high voltage in the ceramic tube, and after the impact electric arc is cut off, the reignition breakdown time is greatly delayed by more than ten to dozens of microseconds; an arc extinguishing current interrupting mechanism is optimized, generated pressure waves are focused to one point on an arc extinguishing channel, larger pressure is generated at the focus, the interrupting capacity is higher, the structure is simple, and the sealing performance is good.
Owner:南宁超伏电气科技有限公司
Flexible Multilevel Bridgeless Power Factor Correction Converter and Modulation Method
ActiveCN107453597BImprove efficiencyReduce the size of the inductorEfficient power electronics conversionEnergy industryCapacitanceDc capacitor
Owner:HUBEI UNIV OF TECH
Knitting member selecting actuator of knitting machine
InactiveCN1259473CFlow inhibitionInhibition leak directionWeft knittingMagnetic reluctanceEngineering
In the knitting member selection actuator of the knitting machine, the reluctance ratio and A magnetic property part (35a, 35b, 45a, 45b, 55a, 55b) having a large magnetic resistance between the knitted members attracted to the suction surface and smaller than the magnetic resistance between the suction surfaces of the adjacent control suction part.
Owner:SHIMA SEIKI MFG LTD
A Balanced Power Supply System for Electric Locomotive Test Line
ActiveCN106208112BGive full play to abilitySimple structurePolyphase network asymmetry elimination/reductionPolyphase network asymmetry reductionTransformerPower balancing
The invention discloses an electric locomotive test wire balanced power supply system which comprises a control unit, a locomotive traction power supply subsystem and a power balanced subsystem. The locomotive traction power supply subsystem is used for converting single phase wire voltage into electric locomotive rated traction power supply voltage; the power balanced subsystem comprises a three-phase V / v wiring transformer and a power balancing device, the primary side of the three-phase V / v wiring transformer is connected with three phases in a three-phase power supply grid of an electric locomotive test wire, the power balancing device comprises two converter units and a direct current capacitor, a first current detection piece is arranged in a primary side loop of a single-phase boosting transformer, the control unit is used for controlling active power facility between the two converter units and each inactive power output according to a current signal of the primary side loop of the single-phase boosting transformer so as to achieve three-phase power grid power balance of the electric locomotive test wire. The power supply system has the advantages of ensuring power supply three-phase balance, eliminating negative sequence influences and the like.
Owner:ZHUZHOU NAT ENG RES CENT OF CONVERTERS
Fully-sealed liquid lightning arrester
PendingCN113594867AProtection against direct lightning overvoltageReduce the amplitudeSpark gap detailsEngineeringStructural engineering
The invention discloses a fully-sealed liquid lightning arrester, which belongs to the technical field of lightning protection and arc extinguishing, and is characterized in that the lightning arrester is a sealed insulating tube, the insulating tube is internally provided with a hollow structure, the hollow structure is filled with insulating liquid, two ends of the insulating tube are provided with electrodes, and the electrodes extend into the hollow structure and are in contact with the insulating liquid. The electric arc is quickly cut off, the electric arc discharges in liquid to generate a liquid-electric effect, impact pressure waves are quickly formed, the impact electric arc is immediately cut off when the impact electric arc is just formed, the reignition of the impact electric arc is delayed, and the continuous discharging condition and the reignition condition are damaged by high voltage in the ceramic tube.
Owner:南宁超伏电气科技有限公司
Transformer winding state diagnosis method, device and system, equipment and medium
The embodiment of the invention discloses a method, device and system for diagnosing the winding state of a transformer, equipment and a medium. The method comprises the steps that a target signal source is controlled to inject broadband signals to M injection phases on the low-voltage side of the transformer at the output frequency i; acquiring the current amplitude of each voltage level group when the broadband signal is injected into each injection phase; according to the current amplitude of each voltage grade group of the mth injection phase, determining a state characteristic curve of each voltage grade group corresponding to the mth injection phase, m being 1 to M; calculating a curve correlation coefficient between the state characteristic curves of the same voltage grade group in each injection phase group; and determining the winding state of the transformer according to the curve correlation coefficient. By means of the mode, signal injection is convenient, the voltage grade of the low-voltage side of the transformer is low, the system impedance of the low-voltage line side is large, broadband signals can be injected into the transformer conveniently, the amplitude of current flowing into and out of the transformer can be obtained online in real time, and the winding fault diagnosis accuracy is higher.
Owner:YUNNAN POWER GRID CO LTD ELECTRIC POWER RES INST
Single-phase five-level boost power factor correction converter
ActiveCN107612304BReduce volumeImprove efficiencyEfficient power electronics conversionAc-dc conversionCapacitanceFull bridge
The invention relates to a single-phase and five-level boost type power factor correction converter, which comprises a diode single-phase full-bridge rectifier circuit, a boost inductor L, a power electronic switch network, a series capacitor network and a parallel resistor network. The boost inductor L is connected between the direct-current positive pole of the diode single-phase full-bridge rectifier circuit and the first end of the power electronic switch network. The second end of the power electronic switch network is connected with the direct-current negative pole of the diode single-phase full-bridge rectifier circuit. In this way, on the premise that a switch frequency and a maximum allowable inductor current ripple are kept consistent, the volume of the boost inductor is reducedby about 75%, and the total volume of the converter is greatly reduced. Or, on the premise that the output power, the switch frequency and the inductor volume are kept consistent, the amplitude of theinductor high-frequency ripple current is reduced by about 75%. The heating of the inductor is greatly reduced, and the efficiency of the converter is improved. The voltage stress of a switch tube can be reduced by about 50%, and the cost is reduced.
Owner:HUBEI UNIV OF TECH
Circuit device
InactiveCN1107439CSmall harmonic distortionReduce current amplitudeElectric lighting sourcesElectric discharge lampsFrequency changerHarmonic
A circuit arrangement for operating a discharge lamp with a high frequency current comprising input terminals for connection to a source of low frequency supply voltage, a rectifier bridge coupled to the input terminals for rectifying the low frequency supply voltage, and an inverter shunting a first capacitor for generating the high frequency current. The circuit arrangement incorporates two power feedback loops to feed power back to an output terminal of the rectifier bridge. As a result the circuit arrangement has a relatively simple configuration, causes only a very limited amount of harmonic distortion and can be realized with relatively cheap and simple components.\!
Owner:KONINKLIJKE PHILIPS ELECTRONICS NV
A Deadbeat Direct Torque Control Method for Switched Reluctance Motor
ActiveCN109546918BHigh precisionReduce lossElectronic commutation motor controlAC motor controlElectric machineMagnetic reluctance
The invention provides a deadbeat direct torque control method of a switched reluctance motor, comprising the following steps: calculating the position angle of the rotor through a photoelectric encoder, and calculating the flux linkage and current of the motor in a rotating coordinate system; The error with the feedback torque and the given flux linkage and the three-phase voltage and current in the stator coordinate system; calculate the space voltage vector in the rotating coordinate system for controlling the operation of the motor in the next beat; obtain six pulse signals to control the motor. The present invention directly controls the torque and flux linkage by controlling the two-phase reference voltage in the rotating reference coordinate system, and controls the flux linkage and torque within one control cycle, so that the torque ripple is smaller and the flux linkage is also significantly reduced .
Owner:DALIAN MARITIME UNIVERSITY
A method for suppressing harmonic current of DC capacitor
ActiveCN107017762BReduce harmonic contentReduce current amplitudeAc-ac conversionDc capacitorCarrier signal
Disclosed is a direct current capacitor harmonic current suppression method. Back-to-back converters are adopted; the active direct current link capacitor current in the back-to-back converters is from superposition of direct currents of a rectifier i<dcr> and an inverter i<dci>; the phases of harmonic components in the two currents i<dcr> and i<dci>are determined by the relative phase PWM carrier waves of the rectifier and the inverter; and by actively controlling and regulating the frequencies and phases of PWM carrier waves in the rectifier and the inverter, the direct current link harmonic currents from the two converter levels can be the same in phases, so that the capacitor harmonic current minimization can be achieved. By adoption of the direct current capacitor harmonic current suppression method provided by the invention, harmonic contents and current amplitudes in the first and second carrier frequency bands in the direct current link capacitor current can be obviously lowered; and by virtue of the method, the power supply mass specification can be satisfied and capacitor current harmonic can be effectively reduced without using a high-capacity direct current link capacitor.
Owner:CHINA THREE GORGES UNIV
A SICM voltage modulation imaging device and method based on differential noise reduction
ActiveCN109387670BImprove the signal-to-noise ratio of the feedback signalImprove signal-to-noise ratioScanning probe microscopyCapacitanceSoftware engineering
The invention relates to a differential-noise-reduction-based SICM voltage modulation imaging device and method. The device comprises a voltage driving unit, a current detecting unit, a signal modulating unit, a feedback control unit and a mechanism executing unit. In addition, the method includes the flowing steps that: a signal generator generates two paths of co-frequency alternating current voltages, wherein one path of voltage is connected to a patch clamp amplifier to serve as a driving voltage and the other path of voltage is connected to a lock-in amplifier to serve as a reference voltage; capacitance compensation is performed by the patch clamp amplifier; one path of modulation voltage having the same frequency and same phase as the reference signal is connected to the lock-in amplifier to carry out feedback signal modulation; calculation is carried out to obtain a new current setting value; and the lock-in amplifier feeds back an extracted current component to a controller, adistance between the probe and the sample is controlled, a track of the relative displacement of the probe and the sample is recorded, and thus image scanning is completed. According to the invention, the feedback signal is modulated to increase the amplitude of the driving voltage, so that the signal-to-noise ratio of the system is improved and thus the Z-direction resolution ratio and the scanning speed of the SICM system are improved.
Owner:SHENYANG INST OF AUTOMATION - CHINESE ACAD OF SCI
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